If ‘$$\div$$’ standsfor ‘$$\times$$’, '-' for ‘+’, '+' for ‘$$\div$$’, then which of the following equationsis correct ?

A

$$21 - 3 + 9 \div 12 = 51$$

B

$$21 + 3 \div 9 - 12 = 75$$

C

$$21 \div 9 + 3 - 12 = 51$$

D

$$21 - 3 \div 9 + 12 = 75$$